Metal hatch pontoon



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K. W. JERNSTROM METAL HATCH PONTOON Filed July 17, 1948 INVENTOR.

/114176-6 y TTP/VVS Aug. 5, 1952 Patented Aug. 5, l 1952 Karl W. Jernstrom, Verona, N. J., assigner to Seaboard Machinery Corporatiom New N. Y., a corporation of NewaYork j York,

Application July 17, 194s, seriairgo. 39,297

This invention relatesto metal hatch elements for ship cargo hatchways. The primary object is to provide a hatch element, particularly a pontoon, which may be simply constructedfrom light-metal, as exempliiied by aluminum and magnesium alloys, using the minimum of metal required'to provide it with the beam strength required when in use, yet with theyelement reinforced to withstand the abuse incidental to its handling, such as is occasioned by its being dropped or banged about.

Certain principles of the invention may prove applicable to the structural metal beam art generally. In this art the use of steel might be preferred.

The principles of the invention may be understood from the following disclosure of a ship hatch pontoon embodying al1 phases of the invention in what is presently considered the best manner.

n the accompanying drawings Fig. 1 is a top View of the hatch pontoon;

Fig. 2 is a side view of Fig. 1;

Fig. 3 is a cross section, of enlarged scale, taken from the line 3--3 in Fig. l; and

Fig. 4 is a longitudinal section in a vertical plane, also of enlarged scale, taken from the line 4--4 in Fig. l.,

These drawings illustrate the hatch pontoon as including two extruded light-metal channels I and 2. Each channel has flanges 3 and 4, respectively, that are thinner than their webs 5 and 6, respectively. in both instances the flanges are at right angles to the webs and have substantially equal depths, and the webs are of equal widths. The flange and web thickness of the two channels are the same. The two iianges are arranged face to face with their flange end edges `ioined together by welding metal applied by welding methods properly applicable to the particular light-metal used.

In the above fashion it is possible to design the pontoon with the proper beam strength while using the minimum of metal. The thicker metal top and bottom, provided by the thicker webs 5 and 6, can be calculated to properly carry the tension and compression, while the thinner sides,

vprovided by the anges 3 and It, can be calculated to carry the compound stress of tension and compression. I-Iowever, calculations leading to a minimum of metal result in the side walls, formed by the flanges 3 and Al, being so thin that they cannot adequately carry the shear stress resulting when the pontoon isabused, as by being dropped or banged during its handling.

With the above in mind, the lower channel sec- 1 can. (ci. iss-s45 f tion ZisY extrudedwith its flange ends inwardly joggedas Aindicated at 'I;l This is done so the 'jogged y'ends lare displaced inwardly t' distances equaling the thickness o-f the flanges 3, and the latter are telescoped about these jogged' ends 'I to produce walls with smooth exteriors. Also, the channelV 2 is extruded to provide "shoulders 8 against whichv the flanges 31 abut when theitwo channels are assembled together. The outer corners of the shoulders and'of the ends of the anges 3 may be chamfered, thus providing grooves for receiving the welding metal 9 joining the two channels together. f

The above results in the relatively thin side walls, of the pontoon, having centrally positioned and longitudinally extending reinforcing ribs which project inwardly of the pontoons sides, where they are out of the way. These ribs reinforce the side walls so that they can carry the shear with which they might be stressed when the pontoon is abused as mentioned. These ribs extend along the neutral axis of the pontoon when it is stressed with bending force, but they perform theirintended function whenever the side walls are placed in shear.

The ends of the pontoon may be closed by end castings I0 having inwardly extending circumferential flanges I I fitting the inside of the pontoon. Blind rivets may be used to fasten these castings, the rivets being applied through the walls of the pontoon and the end casting anges. These end castings may be shaped to clear the ribs provided by the jogs I, or these ribs maybe cut away as required to permit insertion of the end castings I0, the latter being illustrated. In any event, it is considered best to provide the end castings IB with internal reinforcing ribs I2 arranged transversely in line with the reinforcing ribs provided by the jogged ange ends.

A series of strutting plates I3 may be positioned inside the pontoon to support the walls of the box section formed by the two channels. These strutting plates may be bent to have peripheral flanges I4, and formed as required to clear the internal reinforcing ribs. They may be installed by the use of blind rivets in the manner of the end castings.

The drawings illustrate handle basins in the pontoons top. These are not described since the present invention is not concerned with them.

The end castings I and the strutting plates' i3 are preferablymade of the same light-metal; from which the channels are extruded. 'Ihe rivets may also be made of the same metal.

It is obvious from the foregoing that certain phases of this invention are applicable to the structural beam art generally, as previously indcated. 1n such instances it might not be objectionable to jog the flange ends outwardly. In the case of a hatch element it is considered preferable to have the jogs inside so the reinforcing ribs may be out of the way, thus permitting a number tof* the elements to b e-pla'ced close... to: gether. Insome-instances it mightnot'be objectionable to have the upper channel with the jogged ends. element the illustrated construction hasthemadwf., vantage of providing water sheds in the event the lines of welding metal arendiscontinuouseither?-V through inadvertence or intent, This-desirable;

effect cannot be attained when the upperchan.

nel has the jogged ends, exceptinggbyhaying ,they

jogs outwardly of the element where the reinforcing ribs, thus provided, are on the outsider It can be appreciated from the above that while certai-nrpnases :of-1th@ invention-arerapplicablato the structural beam art. generally; that yin the yshipf'hatch'element art they provide and-unexpected results;

A- fmetalship, hatch element: comprising la pair of felongated channe1s-,: each: oft'said'; channels, ineluding afcweb and: havingffanges integralwith saidfweb andlformfed perpendicularthereto, the webs :of fsaidwchannels: being. ithicker thanV their However, in the case `of a hatch-` 4 anges, the flanges of one of said channels being inwardly jogged at the end sections thereof,

thereby defining a shoulder portion, the anges Y of the other of said channels having comparatively straight end sections, which are received by said shoulder portions,'the abutting anges defining a reinforcing rib on the inner surface of saidifelement andfa smoothsurfaceffon the other sidethereof, endclosures-d-isposed transversely at the end points of said element, and a plurality ofV plates transversely positioned along the inner s ur-zlaceso ,f'v said channels, said end closures and plates secured to said channels and providing reinforcement therefor.`

KARL W. JERNSTROM.

, 4I LEEERENCES CITED Thewfollowing references are of record in the le of'this patent:

SIAIES. PATENTS.

Number NameYV Y Date 8545,94? -I-.Izi-ll` ,--fM-e--a-f- May 28, 1907 859,176 Hill Jul-y 2, 1907 (1,161,037 Gross June 3, 1930 FGREIGN PATENTS y Numberl Country. Date 

